Protein Calculator

Protein needs come per kilogram of body weight. The tool multiplies your weight by a range that matches your goal, then suggests a per-meal amount. The ranges come from the dietary reference intake and from sports nutrition research.

Formulas

How it works, step by step

1. First, the calculator converts your weight to kilograms.
2. Then it multiplies that by the low and high end of the range for your goal.
3. Next, it sets a per-meal amount of 0.25 grams per kilogram and holds it between 20 and 40 grams.
4. Finally, it rounds the results to the nearest 5 grams.

Worked example

A person who weighs 75 kg and trains regularly gets a range of 105 to 150 grams a day. Their per-meal amount works out to 0.25 x 75 = 18.75, so the tool raises it to the 20-gram minimum.

Accuracy and limits

The recommended dietary allowance for protein is 0.8 grams per kilogram for adults. Wolfe and colleagues describe it as the lowest intake that meets the needs of nearly all healthy people.

The International Society of Sports Nutrition says 1.4 to 2.0 grams per kilogram a day is enough for most people who exercise. It also suggests about 0.25 grams per kilogram, or 20 to 40 grams, per meal, spread across the day every three to four hours.

A 2018 meta-analysis of 49 trials found that gains in fat-free mass stopped rising above about 1.6 grams per kilogram a day in people doing resistance training. So the Building muscle range starts at 1.6.

• The ranges use your actual body weight, although a dietitian may pick a different reference weight in some cases.
• They describe healthy adults. If you have kidney disease or another condition that affects protein, ask your clinician first.
• The research above does not show that protein beyond these ranges speeds up muscle gain.

Sources

1. Jager R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. Used for: 1.4 to 2.0 g/kg a day for most exercising people and the per-meal dose.
2. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. Used for: Gains in fat-free mass stopped rising above about 1.6 g/kg a day.
3. Wolfe RR, Cifelli AM, Kostas G, Kim IY. Optimizing protein intake in adults: interpretation and application of the Recommended Dietary Allowance compared with the Acceptable Macronutrient Distribution Range. Adv Nutr. 2017;8(2):266-275. Used for: The 0.8 g/kg protein RDA and the 10 to 35% protein range.

Sources and math last reviewed: November 4, 2026.